Preheat your oven to 375°F (190°C) and lightly grease a 9x13 inch baking dish.

In a small bowl, whisk together the soy sauce, brown sugar, pineapple juice, grated ginger, minced garlic, and cornstarch until smooth.

Heat the vegetable oil in a large skillet over medium-high heat. Add the chicken pieces and cook for 3-4 minutes until browned on the outside but not fully cooked through.

Pour the sauce mixture over the chicken and stir constantly for 2 minutes until the sauce begins to bubble and thicken slightly.

In a large mixing bowl, combine the cooked rice, diced red bell pepper, and pineapple chunks.

Add the chicken and thickened sauce mixture to the bowl with the rice and toss gently until everything is evenly combined.

Transfer the mixture to the prepared baking dish and spread it out in an even layer.

Bake for 20-25 minutes, or until the casserole is hot, bubbly, and the peppers are tender-crisp.

Remove from the oven and garnish with sliced green onions and sesame seeds before serving.